A method of speckle reduction in laser replayed holographic images.

摘要

The reduction of speckle in coherent radiation replayed holographic images in achieved by the preparation of a holographic optical element (10) having a plurality of separate sectors (21-24) which constitute efficient transmission elements. A composition hologram of an object (14) made on the recording medium of a plate (13) by making a plurality of successive exposures of the separate sectors in turn using a rotating disc (12) having an aperture (17) therein. The composite hologram is then processed to form a high definition virtual image of the object. Finally the hologram is replayed with each of the separate sectors formed on the holographic optical element in sequence at high speed. The speckle field of the object can be altered by rotating a diffuser (11) in the path of the coherent radiation.